Project Summary The receptor for advanced glycation end products (RAGE) is a multi-ligand pattern recognition cell surface receptor, which upon activation stimulates intracellular inflammatory signaling with implications in diabetes, arthritis, Alzheimer?s and other diseases. The mechanistic understanding of the RAGE signaling axis is poorly understood. Moreover, inhibition of RAGE-ligand interactions represents an attractive potential therapeutic strategy to suppress the symptoms associated with chronic inflammatory processes. This proposal seeks to develop inhibitors of RAGE-ligand interactions to further discern the mechanism of RAGE activation and downstream signaling, as well as to lay the foundation to evaluate the therapeutic potential of inhibiting RAGE to suppress the disease-associated chronic inflammatory processes. Here, we propose to pursue fragment- based molecular discovery based on fragment screening via the Structure Activity Relationship (SAR) by NMR approach. Aim 1 uses SAR by NMR to screen a highly curated library ~ 15,000 fragments. The goal is to identify fragment molecules that bind to different sites within the RAGE-ligand binding interface. The exact location and orientation of the hit fragments will be determined using X-ray crystallography in Aim 2. The crystal structures will then used to elaborate fragments and design linkers between fragments bound to different sites to generate high affinity compounds. In Aim 3, first biophysical and structural techniques will be employed to characterize the specificity of the lead compounds. A selection of the best leads will then be subjected to in vitro cell-based assays to determine the effects on downstream inflammatory signaling.